1. Field of the Invention
The present invention relates generally to construction of buildings and particularly of fairly high and large buildings in which a structural beam framework is initially constructed and other parts are later added and particularly still to construction of such structure from so-called I-beams bolted or welded together and even more particularly to an iron worker's seat or welder's seat which is compact and light enough to be easily transported by a worker and conveniently and easily attached to a horizontal I-beam at or near the bottom of such beam to allow a worker and particularly a welder convenient access to the lower portions of such beam or adjoining or adjacent structures for welding or the like.
2. Preliminary Discussion
In the construction of large buildings, a steel framework formed of structural beams is conventionally erected initially, after which other parts of the building are either attached to or erected around the steel framework. During such construction the construction workers require access to and support on the steel beams including vertical and horizontal I-beams. I-beams are comprised of so-called flanges on the top and bottom connected by an intermediate web between and connecting such flanges. I-beams are very rigid and strong in transverse directions compared with the individual rigidity and strength of their web and flanges as well as with such I-beams overall weight, depending upon the width of both the flanges and central web from which the I-beam is formed. This is because in order to bend the beam in a direction aligned with or parallel to the interconnecting web such as, for example, in a horizontal beam, one entire flange is placed in tension and the other flange in compression with the intermediate web being placed from top to bottom first in tension and then in compression. Furthermore, the beam is also quite stiff or rigid with respect to side forces because such forces are opposed by the width of the beam or, more particularly, one half of the width of the flanges will be placed in tension and the other half essentially in compression with the strength of the flanges in effect being multiplied by two. Such beams can be either produced by a rolling operation in which hot metal in the plastic range is passed through rotating rolls arranged in an H configuration, or, alternatively, can be fabricated from relatively flat structural or heavy sheet or plate sections by welding such sections together in an H configuration. In prior years the best and strongest beams were made from rolled steel sections, but with the demise of heavy rolling mills in the United States due to the widely fluctuating market for such large beams for extremely large buildings or large bridges, both of which are constructed at fairly irregular intervals, most such large I-beams are currently fabricated from sections of flat plate of various thicknesses cut to length and welded together into an H-section, thus saving long distance transportation of large unwieldy beam sections.
I-beams, whether rolled or fabricated, may be either bolted together to form the structure being erected on the job site or more frequently in modern times may be welded together into a building framework. In such welding the welder requires access to the ends or sides of the beam to effect the weld. Access to the sides of vertically erected construction beams is had by hoists or sling seats slung from cranes or derricks or by various climbing aids invented in the past similar to what is used by electric line construction and repairmen and to the upper section or surface of horizontal beams by merely walking on them and sitting or kneeling on them. Thus, access is no great problem with respect to the upper portion of a horizontal beam such as the upper flange, but in a large horizontal beam, such as an I-beam, access to the lower portion of the beam may be difficult unless some sort of scaffold is erected. A welder in particular may require access to the lower flange or the intermediate web by some means other than scaffolding or a sling supported by a crane. Sometimes the welder may lie on the top of the beam and try to reach the web or top of the lower flange with his or her welding torch, but particularly in the case of a large beam, this may be essentially impossible. For this reason a cable may be erected running along the beam and the welder may stand on such cable while working low on the beam or work from scaffolding, which is difficult, or impossible, or at least impractical, except in more elevated positions, or the welder may work from a sling lowered from the top of the beam or otherwise. Yet welding is frequently also necessary on the intermediate sections of large I-beams in order to secure flanges to the main beam for attachment of smaller cross beams, as well as for securing such smaller cross beams to the flanges.
The present inventor has designed a simple but sturdy seat which may be clamped securely usually to the lower portion or flange of a beam, upon which seat a welder can sit with the lower portion and particularly the sides of the intermediate web and top of the lower flange of the beam readily accessible. The seat is basically cantilevered out from the lower flange with the feet of the welder placed on a short footrest for balance, comfort and safety. A safety lanyard may be hooked to or attached from the seat to the usual safety line required by law to be present and run usually lengthwise of the beam to provide a place for the worker to secure or tie off his or her safety line attached to the usual safety belt worn by the worker. Tying off or securing the safety lanyard attached to the seat itself secures the seat in case it should become displaced or dislodged and prevents its fall to lower areas or to the ground with possible serious injury or death to anyone below.
The usual safety tie off line extends along the length of a horizontal beam between the upper and lower flange, which safety cables or securing lines are required by federal law on all high beam structures for welders and other high workers to tie off to, or secure their safety lines to. Thus, if either the welder or the seat of the invention should fall from their position, neither the welder nor the seat will continue on to the ground with damage to underlying personnel or equipment not to mention the welder him or herself. The seat of the invention, being fairly lightweight, can also be carried by a welder or other worker between actual uses slung from the worker's shoulder like a piece of luggage by means of the seat safety line snap attached to the end of the seat.
The seat of the invention comprises an aluminum or aluminum alloy tube or H-section with a flat beam engaging structural section attached or welded to one side at the top of one end and a crosswise seat section welded or otherwise attached to the top at the other end. A wrought steel clamp section, preferably in the form of a C-type-clamp, which is attached to the bottom of the tube section near the inner end of the flat beam engaging sections in a position such that a threaded rotating adjustment member mounted in the upper end of the C-clamp when threaded into its lowest position will contact the top of the flat beam engaging section, or, if one flange of an I-beam is interposed between the two will contact the top of the I-beam flange securely clamping the end of the seat beam to the I-beam flange. The welder may then sit on the seat section at the other end of the seat beam with his or her feet supported upon a short cross-piece at the bottom of a support tube or other structural member depending downwardly from the cross beam upon which the seat member and clamp member are mounted. The footrest section may be pivoted so it can be folded for carrying and the safety strap can, as indicated above, be used as a sling for carrying the seat conveniently over the welder's shoulder or across his back as well as being used to “tie off” or secure the safety seat during use. The provision of a wide flat lower portion or seat for the threaded clamp section allows the safety seat to be securely clamped to an I-beam flange whether such beam is a rolled beam or a fabricated beam and the threaded member preferably has a conventional universally pivoting relatively small diameter end clamp positioned on the end of the threaded member to adjust conventionally to any small angle or top angle of the flange of either a rolled H-beam or a flat flange fabricated H-beam structure. The cantilevered structure with the weight of the welder exerted on the outer end driving or pressing the outer end of the flat friction plate into the bottom of the I-beam with the rotational movement being about the leverage point represented by the point of tightening of the clamp on the upper surface of the I-beam flange provides a very secure attachment. The leverage of the outer end of the friction plate prevents any possible slippage of the seat from the flange even if the clamp has not been securely tightened as long as the clamp is secure enough to form an effective pivot point, although it is, of course, advisable to securely tighten the clamp as well.
3. Discussion of Prior Art
There have been a fair number of inventions directed to use by iron-workers for access to work surfaces during the use of I-beams for building structures, including buildings and bridges, to provide a location or structure from which to safely and conveniently do any necessary work while supported by the framework and usually from the flanges of I-beams. Many of such references deal with clamps of one sort or another for securing a hold on the flanges of either vertical or horizontal I-beams as set forth in the following references.
U.S. Pat. No. 1,312,399 issued to H. H. Heywood, Dec'd, on Aug. 5, 1919, entitled “Device for Climbing Steel Columns,” discloses an apparatus which is strapped to an iron worker's boots or shoes and aids such worker in climbing up and down a structural steel I-beam. A flat plate portion (5) is integrally connected to a laterally directed U-shaped clamp or yoke (6), and a pair of ears (7) are situated at the connection point of the plate (5) and yoke (6). A set screw (10) having a lock nut (11) thereon extends inwardly through arm (9) of U-shaped yoke (6) towards plate portion (5). Similar set screws (12) having lock nuts (13) thereon extend inwardly through ears (7), with set screws (12) being lower than set screw (10) as shown in FIG. 1. In use, as also shown in FIG. 1, the worker secures his feet on plate (5) with straps (14). The device is then adjusted so that the flanges (B) of the I-beam (A) are between the set screws (10 and 12). When the user presses downwardly on plate (5), set screws (12) engage flange (B) and the plate essentially acts as a step for the worker. Heywood generally illustrates the use of a C or U clamping member to secure a support surface to a structural steel beam, although obviously it has nothing to do with securing a seat to an I-beam.
U.S. Pat. No. 1,895,571 issued to J. Hein on Jan. 31, 1933, entitled “Structural Iron Work Climber,” discloses another climber device to assist workers in climbing structural steel beams. Rather than utilizing set screws as in the Heywood invention, Hein utilizes an eccentrically mounted disk (14) or a toothed gripping member (23) as best shown in FIGS. 6 and 8, respectively.
U.S. Pat. No. 2,303,954 issued to A. I. Roke on Dec. 1, 1942, entitled “Safety Device for Workmen on Steel Structures,” discloses a safety rope which is connected to a worker by a harness on one end and which is connected to an I-beam by an anchor (10) on the other end. The anchor is comprised of a bar that fits crosswise across the flange of an I-beam and hooks (23 and 24) which extend inwardly from the ends of the bar so as to fit underneath the I-beam flange. Stabilizing wings (21 and 22) are also provided. Roke generally teaches a safety harness connectable to a steel structure, but the anchor arrangement is different from anything used in the present invention.
U.S. Pat. No. 2,490,923 issued to A. M. Sasgen on Dec. 13, 1949, entitled “Quick Action C-Clamp,” discloses a novel C-clamp arrangement having a lever on one end so that the clamp may be more easily tightly secured to a work surface.
U.S. Pat. No. 2,854,292 issued to J. M. Schaeffer on Sep. 30, 1958, entitled “Welding Chair,” discloses a welding chair for use in welding structural steel beams. Such chair is comprised of a pair of U-shaped side frames connected together by a crossbar (17). Metallic sleeves (10) are welded to the upper ends of the side frames, with hooks (13) slidingly connected to the sleeves (10). As shown in FIG. 3, hooks (13) are secured over the top flange of an I-beam so that the frame structure hangs down below the I-beam on the side of the beam opposite the hooks. The side frames support a seat portion (20) and a footrest portion (21) similar to your seat, but the Schaeffer chair has more of a scaffold-type structural than the seat of the present invention and secured to a beam through a completely different principle.
U.S. Pat. No. 3,011,587 issued to P. H. Mallog on Dec. 5, 1961, entitled “Supporting Device,” discloses a support for a seat for working on steel beams which is comprised of a vertically disposed steel channel or tube (10), a seat or support structure extending outwardly from the channel (10), a footrest bar (26), and a means (12) for securing the structure to the flange of a structural beam. The seat (24) and footrest (26) are connected to channel by sleeve (22) so that the vertical position of the seat and footrest is adjustable. The securing means as shown in FIG. 1 includes a pair of strap members (17) and adjustable extension members (18) which extend across the top of a I-beam flange. A cross strip (20) connects extension members (18), and a C-clamp (30) is used to secure cross strip (20) to the flange. Once connected, the worker then lowers himself into the seat (24). The Mallog support device shown in FIG. 1 is somewhat similar to the present invention in that (1) a C-clamp is used to secure the seat to a structural steel beam, and (2) single steel channels comprise the actual seat and footrest portions of the structure. FIG. 3 illustrates an embodiment wherein the device is arranged so that work can be performed under the beam. Note in FIGS. 2-3 that the seat can be swung radially so that it extends underneath the beam. U-shaped member (33) is bolted around the upper end of steel channel (10), and a plate (34) is situated so that it is over the lower flange. C-clamp (35) is then used to engage both plate (34) and the flange so that the device is secured to the beam. A safety rope and harness is also not provided. The principle by which the seat is secured to the beam as well as the arrangement of the seat overall differs, however, from the present applicant's arrangement.
U.S. Pat. No. 3,137,487 issued to F. Lesser on Jun. 16, 1964, entitled “Safety Belt for Scaffolds,” discloses a line connected to a worker by a harness or strap on one end and connected in a cylindrical tube on its other end. The tube is connected to a somewhat unique and rather large C-clamp (60) by an arm (17) and stem (62), and the C-clamp is then secured to one flange of the structural beam. Lesser illustrates the use of a single large C-clamp to secure a worker to a beam albeit via a line rather than a seat structure.
U.S. Pat. No. 3,183,997 issued to H. P. Kleiss on May 18, 1965, entitled “Suspended Working Platform Unit,” discloses a platform for use in inspecting, maintaining and the like areas such as the inner walls of closed tank structures. The platform is comprised of a vertical support shaft suspended from a carrying member which is mounted above a tank cover plate and having a platform connected to the lower end of the carrying member. Kleiss illustrates another platform for enabling a worker to work underneath a surface while suspended from such surface.
U.S. Pat. No. 3,217,833 issued to D. W. Smith on Nov. 16, 1965, entitled “Safety Device,” discloses a safety line for attachment to an iron worker having cooperative J-shaped jaw members which are fitted and locked over the top flange of an I-beam. A worker is secured via a safety strap connected to an elongated bar which is pivotally connected to the worker and J-shaped jaw member. Smith generally teaches another safety harness connected to a device which is removably connected to an I-beam, although such arrangement is not designed to support a worker while working or welding on the underside of a steel beam.
U.S. Pat. No. 3,336,642 issued to R. H. Armacost on Aug. 22, 1967, entitled “Clamp With Preset Tension,” discloses another alternative C-clamp arrangement wherein the pressure applied by the clamp to the surface being held may be easily and precisely regulated.
U.S. Pat. No. 3,731,762 issued to J. M. Sirls on May 8, 1973, entitled “Hunting Chair,” discloses a chair comprised of a tubular frame structure and including a simple seat member and footrest. As shown in FIG. 5, the chair is designed to be portable so that it may be carried into the woods and deployed in a suitable hunting position. The seat, however, is not clamped to a tree branch or the like using a C-clamp but rather utilizes an arcuate hanger rod having teeth which is secured over a tree limb. A cable and winch arrangement is also provided to aid the user in elevating the chair to the desired position.
U.S. Pat. No. 4,171,032 issued to H. J. Woolslayer et al. on Oct. 16, 1979, entitled “Safety Support for Safety Belts,” discloses a support for attachment to a worker safety harness and lanyard arranged so that the worker may move about a fairly large work area yet the lanyard is suspended so that they worker will not fall a large distance in the event of an accident. A vertical sleeve (3) is connected to a structural beam by hooked bolts (5) which are secured to the sleeve by crossbars (4). A slightly angled long vertical pole (8) is rotatably connected to the sleeve, and the lanyard (16) is connected to the upper end of the pole (8).
U.S. Pat. No. 4,271,927 issued to G. S. Brown et al. on Jun. 9, 1981, entitled “Inspection or Maintenance Cradle,” discloses a rolling cradle suspended from an I-beam or overhead track. As shown in FIGS. 1 and 8, three roller assemblies are provided on each end of the structure, which assemblies are selectively temporarily removable from the beam or track to facilitate bypassing various obstructions. Brown et al. generally illustrates a more complex, permanent type work platform than your proposed welding or work seat.
U.S. Pat. No. 4,368,801 issued to D. D. Lewis on Jan. 18, 1983, entitled “Column Climbing Device,” discloses another device which is worn on the feet of the climber and includes spaced apart jaws which grip opposite edges of the same flange of a structural steel girder. The Lewis jaws apparently are an improvement over the previous foot attachable climbing devices in that they can be more easily moved out of the way when not in use so that the wearer can walk.
U.S. Pat. No. 4,424,760 issued to F. A. Grufman on Jan. 10, 1984, entitled “Hanging Chair,” discloses a chair such as a boatswain's chair having a seat, backrest, and a frame comprised of a continuous hose to which the seat and backrest are connected. The chair is apparently meant to hang from a rope rather than being connected to a rigid surface such as an I-beam.
U.S. Pat. No. 4,928,789 issued to S. C. Claeys on May 29, 1990, entitled “Iron Worker's Seat Protector and Gripping Device,” discloses a seat protection and gripping arrangement for aiding a worker in more comfortably and securely straddling a steel beam. First, a flexible sheet preferably made of conveyor belting having a smooth inner surface and textured outer surface is provided. Also provided is a waist strap (see FIG. 1) so that the sheet can be fastened loosely adjacent the inner leg and rump area of the worker. As shown in FIGS. 5 and 6, when a worker straddling an I-beam grips such beam with his legs, the sheet member is disposed between the legs and the beam. Also provided, as shown in FIG. 1, is a C-clamp which is used to secure the flexible sheet to the top flange of the I-beam so that it cannot slide on a sharply angled beam.
U.S. Pat. No. 5,048,640 issued to J. J. McConville et al. on Sep. 17, 1991, entitled “Work Platform Supported by Structural Beams,” discloses a movable work platform arranged so as to be suspended from and roll between a pair of structural steel beams. The McConville et al. platform is indicated as being mostly used between large beams used in bridge construction, and is designed to take the place of a large amount of scaffolding otherwise needed to allow workers to perform required work between the beams.
U.S. Pat. No. 5,165,499 issued to M. Bell on Nov. 24, 1992, entitled “Anchor System for Use With Fall Prevention Safety Devices,” discloses another strap for anchoring a worker to a structural beam. The Bell strap includes a ratchet-type fastening device which is secured around the circumference of a structural beam.
U.S. Pat. No. 5,607,029 issued to D. K. Beckham on Mar. 4, 1997, entitled “Safety Device,” discloses another safety device comprised of an upright, elongated post (12), a lower jaw (13) which fits under the lower flange of a structural beam, and an adjustable upper jaw (14) which fits over the upper flange of a structural beam and is basically in the form of a C-channel. Beckham generally teaches another arrangement for connecting an apparatus to a steel beam or column.
U.S. Pat. No. 5,730,245 issued to J. Conway on Mar. 24, 1998, entitled “Safety Cable Deck Anchor,” discloses an anchor system for worker safety cables which is designed to be slipped over and clamped to the upper flanges of two I-beams. The device is made of three main layers preferably all made of steel and welded or otherwise interconnected. The inner layer is slightly shorter than the outer layers so that a space is created large enough for the ends of the I-beam flanges to be fitted. Setscrews are then used to anchor the platform to the beams. Conway generally illustrates an anchor having a multi-layered plate arrangement such as used with your clamping system.
U.S. Pat. No. 6,053,279 issued to J. McKenna on Apr. 25, 2000, entitled “Structural Beam Safety Attachment,” discloses another means for attaching a safety belt to a structural beam. The McKenna attachment is comprised of first and second components (11 and 12) connected together by a clamp (17). The main components each have a U-bend which fit over the sides of the I-beam flange, and the clamp is then used to bring the bends together so that the device is locked to the beam. The clamp is attached to a tether which is then attached to a worker in the usual manner.
U.S. Pat. No. 6,227,330 issued to M. A. Preusser et al. on May 8, 2001, entitled “Support Structure for Suspending a Work Surface Below a Girder,” discloses platform which is suspended from the underside of a bridge. Note that the platform is secured to an I-beam flange or web by four clamp members (23). Preusser et al. generally teaches a suspended platform which is attachable to an I-beam by C-clamp, although structurally such platform is completely different from the present applicant's portable seat. U.S. Pat. No. 6,302,238 also issued to Preusser et al. is a continuation application of the '330 Preusser et al. patent.
While there have thus been work chairs for working under and around steel beams, including I-beams, and C-clamp or other type clamps to hold various working equipment including seats and safety devices and arrangements for use in working and attached to structural beams, no previous device, so far as is known to the present inventor, has provided the benefits in safety and convenience of the present inventor's working or welding seat arrangement. Not only is the present inventor's working seat more securely attached to the flanges of an I-beam where the welder can see that it is secure, but the seat of the invention has a construction and lightness that enables it to be easily transported by the welder from place to place where it can be used or is to be used.